.parent {
    width: 500px;
    background-color: skyblue;
    color: white;
    padding: 15px;
}
.child {
    width: 100%;
    background-color: pink;
    color: white;
    padding: 15px;
}
.grand {
    width: 100%;
    background-color: #bfa;
    color: white;
    padding: 15px;

}